The present invention relates to a warp yarn breakage detecting and indicating apparatus which provides a stop signal upon the detection of warp yarn breakage on a loom and indicates the exact position of warp yarn breakage.
The warp yarn breakage detecting apparatus of a dropper system has well been known in the textile industry. The known warp yarn breakage detecting apparatus comprises a plurality of droppers hung on warp yarns, respectively, of a warp, and a dropper bar disposed under the warp so that the droppers will fall thereon when the associated warp yarns are broken, and detects the drop of a dropper thereon electrically to provide a stop signal for stopping the loom.
It has been found that the reliability of the warp yarn breakage detecting apparatus of a dropper system is enhanced through the improvement of the contact between the dropper and the dropper bar, and a technique has been proposed to apply a voltage of more than 50 V to the dropper bar.
On the other hand, a warp yarn breakage indicating apparatus has been developed to enable efficient work for searching and repairing a broken warp yarn after the loom has been stopped, by indicating the position of the broken warp yarn. This warp yarn breakage indicating apparatus employs a dropper bar formed of a longitudinally continuous electrically resistive member and specifies the position of the dropper which has dropped on the dropper bar, by measuring the electric resistance of a portion of the electrically resistive member between one end of the same and a position where the dropped dropper came into contact with the electrically resistive member.
The respective requisite characteristics of the warp yarn breakage detecting apparatus and the warp yarn breakage indicating apparatus will be described comparatively hereinafter.
The warp yarn breakage detecting apparatus is desired to be able to function at a high operating speed which will not cause the malfunction of the warp yarn breakage detecting apparatus due to the vibration of the loom to limit the defect formed on the fabric by warp yarn breakage to the least possible extent so that the defect can simply be repaired.
On the other hand, the warp breakage indicating apparatus is desired to be able to provide a sufficiently stable measurement signal for highly reliable detection of the position of the broken warp yarn and for the indication of the position of the broken warp yarn. Accordingly, the measurement signal must be processed by a measurement signal processing circuit having a sufficiently large time constant in a state where the mechanical vibration of the dropper does not occur. Such an operation is unable to be achieved at a high speed.
Thus, the warp yarn breakage detecting apparatus and the warp yarn breakage indicating apparatus are contrary to each other in the operating speed. Furthermore, it is preferable to apply a high voltage to the dropper unit of the warp yarn breakage detecting apparatus to ensure the reliable operation of the warp yarn breakage detecting apparatus, whereas it is preferable that the warp yarn breakage indicating apparatus operates on the lowest necessary voltage to avoid the useless heat generation of the electrically resistive member.
Accordingly, two types of dropper units, which require troublesome work for operation, need to be provided unavoidably entailing a serious problem that the constitution of the loom becomes complex when the warp yarn breakage detecting apparatus and the warp yarn breakage indicating apparatus are provided individually on the loom.